NAVIA Sense: the IGC recorder, calibration and the compass swing

The NAVIA Sense is the air data and inertial platform of the NAVIA system: pressure sensors, GNSS, outside air temperature and — on most versions — an AHRS with an integrated magnetometer, in one small box that feeds everything else in the aircraft. On the gliding versions it is also a secure IGC flight recorder, which changes what you are allowed to do to it.

This article covers choosing the right version, installing it, what the calibration certificate replaces, and the two commissioning steps that decide whether your attitude and heading are honest. Pin allocations and dimensions are in the installation manual and are not repeated here.

Which Sense you have

Two capabilities are software licences rather than hardware: the IGC flight recorder on the gliding versions, and Gliding Pro+, which uses the inertial platform to compute real-time air mass movement for markedly better vario and wind data. Field pressure calibration is optional across the range.

The IGC recorder

Where the licence is enabled, the Sense is a high-level approved logger, which means its files are valid for FAI badge claims, diplomas and world record flights without further argument.

It records at a fixed 1 Hz — one track point per second, with no setting to adjust, so every log carries full resolution whether or not anyone remembered to configure it. Flight detection is automatic: recording begins when the unit sees takeoff parameters and finalises the log after landing. In an integrated installation the files transfer to the Core Pro and are downloaded through a connected display.

Every file ends with a G-record, the cryptographic signature that lets a scrutineer prove the file has not been edited. Alter the file by hand and validation fails, which is the entire point. Give the GNSS antenna a clear view of the sky: continuous tracking and valid signatures both depend on it.

Engine noise, and when the internal sensor is not enough

The Sense carries an internal acoustic ENL sensor, and for a glider with a standard piston engine that is entirely sufficient to detect and record engine operation.

Jets and electric propulsion defeat it — one has the wrong acoustic profile, the other has almost none — so those aircraft need an external means-of-propulsion sensor to produce valid engine data in the IGC file. Neither version is a standalone device: both depend on the Sense to process, record and forward everything they measure, and both connect to its secondary serial port.

MOP Jet

An acoustic sensor tuned to the high-frequency noise a jet produces, mounted near the engine and ideally above the wing spar. Because high-frequency sound is strongly directional, plan on several test flights to confirm it is genuinely capturing engine noise in the recorded file rather than in theory.

MOP Electro

This one measures electricity rather than sound: propulsion battery voltage through its high-voltage connector, and current through a clamp placed over the main high-current lead. Beyond satisfying the IGC engine record, it gives the pilot live current flow and the energy consumed in kWh over the flight — which is what electric glider competitions enforcing a daily energy cap actually need.

Disconnecting either MOP in flight is a clear violation of the file's integrity: the recorded values drop for the remainder of the flight and the engine record is void. Wire it so it cannot be disturbed, and keep the high-voltage lines strictly on the high-voltage connector — putting them on the data port destroys the module and whatever is attached to it.

The security seal and the internal battery

To qualify as a highest-level recorder — the standard required for world records, the top badges and all competition flying — the Sense carries a dedicated internal battery that keeps its hardware tamper switches alive and watching even when the aircraft is completely unpowered.

That battery is expected to last more than five years, and we strongly recommend replacing it every five years during the barocalibration, while the unit is with us anyway. If it does run down first, the portal and any connected displays show Seal not valid. The unit keeps working and keeps recording IGC files, but those files carry no valid G-record, so they cannot verify flight integrity for a claim or a competition.

There are no user-serviceable parts inside. Opening the enclosure trips the tamper switches and permanently invalidates the IGC seal — only a factory service can re-seal it. Battery replacement, recalibration and every hardware repair happen at LX navigation or an authorised partner.

Standalone operation and the Wi-Fi portal

Connected to a Core Pro, the Sense has no user interface of its own: logger settings, task declaration, pilot event triggering and flight downloads all happen through the displays, and its standalone Wi-Fi is switched off.

Used standalone, it raises its own access point named Navia Sense xxxxx, where the digits are the unit's serial number, with a password unique to that device. Join it and the portal appears; if it does not, browse to 192.168.4.1. From there you can check and download the logbook, transfer waypoints, create and declare tasks, configure pilot, co-pilot and aircraft details, and trigger a pilot event.

Mounting, and why your screwdriver matters

The Sense mounts on M2 threaded holes on each side, and screws that are too long will damage the internals. Two things then decide whether the AHRS is worth anything: the orientation, and the magnetism.

Orientation is critical. The unit must be installed with the pneumatic and electrical connectors pointing forward, in the direction of flight, and the top of the unit facing up — the case carries an aircraft silhouette and the words THIS SIDE UP to make the point. Mounted any other way, the pitch and roll it reports are simply wrong. Mount it as far as practical from ferrous metal, high-current cables, motors and anything with moving magnetic parts.

Units with AHRS contain a highly sensitive magnetometer. Use non-magnetic tools — beryllium, copper or titanium — and never a magnetised screwdriver. Exposure can permanently alter the unit's internal magnetic signature.

Take normal electrostatic precautions when handling the connector and its wiring, and double-check the pinout before applying power. The Sense is a 5 V device fed from the Core Pro's regulated output: connecting it to a 12 V or 24 V bus destroys it immediately and permanently.

Pneumatics

The Sense uses female threaded ports and push-in connectors for 6 mm hose. Static and total pressure come from the aircraft's existing pitot-static system — locate the existing lines and, where no free port exists, split them with a T-junction. Gliders with a total energy probe connect it to the TE port. Angle of attack applies only to the Airplane Pro and Pro HS versions, which take their AOA lines from a compatible pitot-AOA probe; AOA can be compensated for flap position, which needs either a flap position sensor or a discrete input wired to the Core Pro.

Keep every run as short as the airframe allows, airtight, free of sharp bends and twists, and arranged so water cannot get in. A leak test is not a regulatory requirement for the AOA system, but inconsistent performance or a refusal to calibrate is exactly the symptom it exists to diagnose.

The GNSS antenna and outside air temperature

Install the GNSS antenna horizontally with its marked face to the sky, and give it a genuinely clear view. Non-conductive covers — fibreglass, glass, wood, cloth — are fine; metal and carbon fibre are not, so an antenna under a carbon panel will never work properly no matter how good it is.

Hand-tighten SMA connectors, firmly, and never with tools. An over-tightened connector cannot be removed later without the receptacle spinning inside the chassis, which twists and breaks the delicate internal coaxial cable.

At least one outside air temperature probe is required, because true airspeed and density altitude are computed from it. A 3-wire probe actively compensates for cable resistance and is what the Sense expects; a 2-wire probe works too, with the appropriate pins bridged at the connector, since the cable error in a light aircraft is generally negligible. In an installation with more than one Sense, temperature is shared through the Core Pro.

Calibration and certification

Every unit is factory-calibrated at multiple points, with linear interpolation applied internally, so the data it records and reports is already calibrated. That is why there is no longer a traditional barochart: instead, each device is issued a formal Certificate of Calibration naming the calibration tool, the date, the next due date and the operator. It satisfies the requirements for badges, records and international competitions in full.

For any device using the IGC recorder the recalibration interval is five years. At that point the unit comes back to us or to an authorised partner for recalibration of its altitude sensors and replacement of the security battery, and its highest-level approval continues. The portal shows both the last calibration date and the due date, so you never have to guess.

User calibration through the Wi-Fi portal is available on top of the factory baseline, and it fine-tunes the live data sent to your displays and instruments.

User calibration is never applied inside the secure IGC file. Adjust it as you like for the panel; the sporting record is untouched by it, deliberately and by design.

Levelling the AHRS and the compass swing that isn't one

Two commissioning steps, one on the ground and one in the air.

1. Level the AHRS. With the aircraft standing in its normal straight-and-level flight attitude, trigger the CAGE command — from the Wi-Fi portal standalone, or from Airplane Settings › Navia Sense on a display. This establishes the baseline the horizon is drawn against, so getting the attitude right matters more than getting it done quickly.
2. Teach the compass. There is no compass rose in this procedure. The magnetometer calibrates itself in flight, using its algorithm together with the internal gyros. Fly a few figure-of-eight patterns to let it gather magnetic data in every direction, and when you are satisfied the heading readout is accurate, execute Save compass from the same menu.

Saving stores the calculated magnetic offsets, and from the next flight the compass shows the correct heading immediately from boot-up, stationary on the ground. Skip that step and it will keep re-learning from scratch, every flight, forever.

Post-installation checkout

1. Power up and confirm the Sense appears on a display, or broadcasts its access point standalone.
2. Move the aircraft out of the hangar and verify a valid 3D GNSS fix.
3. Check the horizon reads level after CAGE, and that pitch and roll respond smoothly when the aircraft is rocked.
4. Confirm airspeed reads zero with the pitot uncovered and the aircraft stationary.
5. Confirm every pneumatic line is connected and leak-checked before the panel goes back on.

When something is not right

Where to go next

• What the recorder is actually producing, and how it is verified: the Academy article on IGC logs.
• The sensors behind the numbers: AHRS, compass and magnetometer, pitot and static systems and altitudes.
• Where the Sense fits: NAVIA system architecture and commissioning a new aircraft.
• Barocalibration, battery replacement and repairs: send it in, or ask us first.
• The device itself: NAVIA Sense.